Camellia Flower Blight. Oh so sad, oh so common. But fear not, help is available!
Camellia flower blight is what happens when your lovely blossoms turn brown and drop off prematurely.
The condition is caused by a fungus, Ciborinia camelliae. Rainy, humid weather is the culprit, and since camellias usually flower at this time of year, well, there lies the rub.
You can both prevent and manage the problem.
Prevent the blight by removing the infected flowers from the plant and the ground (but don't add them to the compost pile!) The fungus spores on the buds will go into the ground and can stay dormant for years, recurring each spring.
Manage the problem in a number of ways:
Avoid overhead watering. Cover the soil under the bushes with a few inches of organic mulch to help kill off spores. Prune out thin, old, or low hanging branches to promote air circulation.
If you want to spray a fungicide, I recommend using a product with neem oil, which is organic. Spray the plant and the soil around it.